Background: Delusional jealousy is a major motive for violence and is sometimes found in demented patients. This study was undertaken to investigate the frequency and the characteristics of delusional jealousy in demented patients.

Method: The sample population consisted of 133 demented patients admitted to the geropsychiatric ward. Patients with and without delusional jealousy were compared in terms of general characteristics and psychotic symptoms.

Results: Of the 133 demented patients, 21 (15.8%) showed delusional jealousy. Delusional jealousy was found in various types of dementia. There were no significant differences between the two groups in regard to age, age at onset, gender, educational level, and Mini-Mental State Examination score. All patients with delusional jealousy had at least one other psychotic symptom.

Conclusion: Delusional jealousy is a common problem in dementia. The psychobiological factors of delusional jealousy and cognitive function in demented patients may differ. There may be various underlying factors for the development of delusional jealousy in dementia.